Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats

Abstract Purpose: To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats. Methods: Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis. Results: Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05). Conclusions: Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

Sonographic patterns of Peyronie's disease in patients with absence of palpable plaques

ABSTRACT Purpose Non-palpable isolated septal plaques of the penis are likely present in a significant number of patients affected by erectile dysfunction (ED) and penile pain without deformity or curvature. The aim of this study was to evaluate the ultrasound (US) patterns observed in patients investigated for ED or penile pain without curvature. Materials and Methods We reviewed the medical records of 386 patients who underwent an initial colour-Doppler ultrasonography (CDU) of the penis for DE and/or penile pain without curvature. After satisfying inclusion criteria, 41 patients were individualized. All patients had a non-palpable plaque with involvement of the penile septum. Three US patterns were identified: focal hyperecoic thickening of the intercavernosum septum (IS) with acoustic shadow (pattern 1), non-calcified thickening (isoechoic or slightly hyperechoic (pattern 2), and microcalcifications in the IS without associated acoustic shadow (pattern 3). Results Patients' mean age was 51.3±16.7. ED was the predominant disorder in 73.2% of patients, followed by penile pain and length loss in 19.5% and 7.3% of patients, respectively. 32(78.1%) patients showed the pattern 1, 6 (14.6%) pattern 2, and 3 (7.3%) pattern 3. Plaques size varied from 3 to 13 mm. The penile hemodynamic response to CDU reported abnormal findings distally to the septal plaques in 20 patients (<25cm/sec). Median left and right cavernosum artery flows measured a peak systolic velocity of 31cm/sec and 33 cm/sec, respectively. Conclusions We believe that an US study with CDU provides a way to characterize, localize, and deliver treatment choice in patients with Peyronie's Disease.

Penile microvascular endothelial function in hypertensive patients: effects of acute type 5 phosphodiesterase inhibition

The primary aim of this study was to evaluate penile endothelial microvascular function in patients with primary arterial hypertension and age-matched normotensive subjects using laser speckle contrast imaging (LSCI). Additionally, we analyzed the acute penile microvascular effects induced by oral phosphodiesterase type 5 inhibitor (sildenafil; SIL) administration. Endothelium-dependent microvascular reactivity was evaluated in the penises and forearms of hypertensive patients (aged 58.8±6.6 years, n=34) and age-matched healthy volunteers (n=33) at rest and 60 min following oral SIL (100 mg) administration. LSCI was coupled with cutaneous acetylcholine (ACh) iontophoresis using increasing anodal currents. Basal penile cutaneous vascular conductance (CVC) values were not significantly different between control subjects and hypertensive individuals. Penile CVC values increased significantly after SIL administration in control (P<0.0001) and hypertensive (P<0.0001) subjects. Peak CVC values were not different between the two groups during penile ACh iontophoresis before SIL administration (P=0.2052). Peak CVC values were higher in control subjects than in hypertensive subjects after SIL administration (P=0.0427). Penile endothelium-dependent microvascular function is, to some extent, preserved in patients presenting with primary arterial hypertension under effective anti-hypertensive treatment. LSCI may be a valuable non-invasive tool for the evaluation of penile vascular responses to phosphodiesterase type 5 inhibitor.

The possible protective effects of dipyridamole on ischemic reperfusion injury of priapism

ABSTRACT Purpose To investigate the protective effects against ischemia reperfusion injury of dipyridamole in a model of induced priapism in rats. Materials and Methods Twenty-four male Sprague-Dawley rats were divided into four groups, control, P/R, P/R+DMSO and P/R+D. 3ml blood specimens were collected from vena cava inferior in order to determine serum MDA, IMA, TAS, TOS and OSI values, and penile tissue was taken for histopathological examination in control group. Priapism was induced in P/R group. After 1h, priapism was concluded and 30 min reperfusion was performed. In P/R+DMSO group 1ml/kg DMSO was administered intraperitoneally 30 min before reperfusion, while in P/R+D group 10mg/kg dipyridamole was administered intraperitoneally 30 min before reperfusion. Blood and penis specimens were collected after the end of 30 min reperfusion period. Sinusoidal area (µm2), tears in tunica albuginea and injury parameters in sinusoidal endothelium of penis were investigated. Results Histopathological examination revealed no significant changes in term of sinusoidal area. A decrease in tears was observed in P/R+D group compared to P/R group (p<0.05). Endothelial injury decreased in P/R+D group compared to P/R group (p>0.05). There were no significant differences in MDA and IMA values between groups. A significant increase in TOS and OSI values was observed in P/R+D group compared to P/R group. A significant decrease in TAS levels was observed in P/R+D group compared to the P/R group. Conclusions The administration of dipyridamole before reperfusion in ischemic priapism model has a potential protective effect against histopathological injury of the penis.

The vascular and neurogenic factors associated with erectile dysfunction in patients after pelvic fractures

ABSTRACT Erectile dysfunction (ED) is a common complication of pelvic fractures. To identify the vascular and neurogenic factors associated with ED, 120 patients admitted with ED after traumatic pelvic fracture between January 2009 and June 2013 were enrolled in this study. All patients answered the International Index of Erectile Function (IIEF-5) questionnaire. Nocturnal penile tumescence (NPT) testing confirmed the occurrence of ED in 96 (80%) patients on whom penile duplex ultrasound and neurophysiological testing were further performed. Of these ED patients 29 (30%) were demonstrated only with vascular abnormality, 41 (42.7%) were detected only with neural abnormality, 26 (27.1%) revealed mixed abnormalities. Of the 55 patients (29+26) with vascular problems, 7 patients (12.7%) with abnormal arterial response to intracavernous injection of Bimix (15mg papaverine and 1mg phentolamine), 31 (56.4%) with corporal veno-occlusive dysfunction and 17 (30.9%) had both problems. Of the 67 (41+26) patients with abnormal neurophysiological outcomes, 51 (76.1%) with abnormal bulbocavernosus reflex (BCR), 20 (29.9%) with pathological pudendal nerve evoked potentials (PDEPs) and 25 (37.3%) with abnormal posterior tibial somatosensory nerve evoked potentials (PTSSEPs). Our observation indicated that neurogenic factors are important for the generation of ED in patients with pelvic fracture; venous impotence is more common than arteriogenic ED.

Relationship between pseudoexfoliation syndrome and erectile dysfunction: a possible cause of endothelial dysfunction for development of erectile dysfunction

Pseudoexfoliation syndrome (PES) is a common age-related fibrillopathy related to accumulation of pseudoexfoliation material (PEM) in certain places in the body, especially blood vessels. Erectile dysfunction (ED) is another condition related to vascular pathology and in this study it is aimed to identify the relationship between ED and PES.

False fracture of the penis: different pathology but similar clinical presentation and management

Penile fracture is the most common presentation of acute penis. Rupture of the superficial dorsal penile vein [s] may mimic penile fractures with similar clinical presentation but with intact corporeal bodies. Our aim of the study is to highlight superficial dorsal penile vein [s] injury as true emergency with better prognosis. Sixty-eight patients with suspected penile fractures presented to our hospital between June 2007 and January 2013. Out of these, 11 patients showed intact tunica albuginea on exploration with injured dorsal penile vein [s] identified. Records of such 11 cases were reviewed regarding age, etiology, symptoms, physical signs, findings of surgical exploration and post-operative erectile function. All 11 patients were injured during sexual intercourse and presented with penile swelling and ecchymosis and gradual detumescence. Mild penile pain was encountered in 5 cases and the "snap" sound was noted in 2 cases. Examination revealed no localized tenderness, or tunical defect. All the patients regained penile potency without deformity after surgical ligation of the severed vessels. One patient developed penile hypoesthesia. Although the classic "snap" sound and immediate detumescence are usually lacking in the symptomology of dorsal penile vein rupture, its clinical presentation can be indistinguishable from true penile fracture. Surgical exploration is still required to avoid missing tunical tear with possible future complications. The long-term outcome and prognosis are excellent

Sinusoidal Constriction and Vascular Hypertrophy in the Diabetes-Induced Rabbit Penis

Objective To assess the morphological changes of penile vascular structures and the corpus cavernosum area in alloxan-induced diabetic rabbits. Materials and Methods Twenty male rabbits (2 months old) were divided into two groups with 10 rabbits each, the control group (CG) and the diabetic group (DG). The animals from DG received an intravenous injection of alloxan (100mg/kg) to induce the diabetes. Ten weeks after the induction of diabetes, all animals were euthanized. Two fragments of the penile shaft were harvested and samples were processed and paraffin embedded. Sections (5µm) were cut and stained for histological and immunohistochemical markers. Results Nuclear protrusion toward the lumen, and cytoplasmic vacuolization were observed in the tunica intima of the dorsal artery of the penis in DG. The thicknesses of the tunica media increased significantly in DG (p = 0.0350). It was also observed a significant increase in the area of the tunica media (p = 0.0179). There was no significant change in smooth muscle cell density in the tunica media of the dorsal artery of the penis (p = 0.0855). The collagen fiber pattern of the tunica adventitia of the dorsal artery of the penis was different between the control and diabetic groups. There was a significant decrease in the area occupied by the cavernous sinuses in DG (p = 0.0013). Conclusion Alloxan-induced diabetes mellitus in rabbits promotes important changes in penile vascular structures, thereby decreasing blood supply and affecting penile hemodynamics, leading to erectile dysfunction. .

[Peak systolic velocity of cavernosal artery of the penis before and after papaverine injection in erectile dysfunction]

Sexual dysfunction in males is characterized by the inability to achieve or maintain an erection sufficient for a satisfactory sexual activity. Erectile dysfunction is a common disorder in males and intracavernosal injection of papaverine followed by color Doppler ultrasonography of the penis is used to diagnose and treat vascular impotence. In this study, we examined the relationship between changes in peak systolic velocity [PSV] and erectile dysfunction with vascular cause after a cavernosal injection of papaverin. We performed this self-controlled clinical trial in Shahid Hasheminejad Hospital in Tehran, Iran during 2010 and 2011. The study population consisted of 90 patients with erectile dysfunction. The peak systolic velocity [PSV] of cavernosal arteries was evaluated before and after injection of 40-80 mg papaverine and it was compared in the patients with and without response to injection. The mean age of participants was 47.7 +/- 13.7 years. Response to papaverine injection was positive in 41[45.5%] patients. The mean PSV values were 14.68 +/- 5.65 and 53.74 +/- 18.8 cm/s before and after the injection, respectively [P<0.001]. A PSV cut-off point of 10 cm/s was determined for the condition before injection. The sensitivity and specificity of the value for diagnosis of arterial erectile dysfunction were calclulated as 50% and 100%, respectively. A PSV cut-off point of 10 cm/s in flaccid status before papaverine injection has a low sensitivity but high specificity for the diagnosis of arterial erectile dysfunction. Future studies with sufficient cases of arterial erectile dysfunction are necessary for final judgments and suggestion a new cut off point

Alterações do tecido conjuntivo e músculo liso no pênis de coelhos diabéticos / Connective tissue and smooth muscle alterations in diabetic rabbit penis

Introdução: Embora a disfunção erétil seja um problema frequente em pacientes com diabete mellitus, poucos estudos avaliaram as alterações da estrutura peniana nesta condição. Objetivo: Avaliar a densidade volumétrica de colágeno, fibras do sistema elástico e células musculares lisas no corpo cavernoso (CC), corpo esponjoso (CE) e túnica albugínea (TA) no pênis de coelhos diabéticos. Método: Vinte seis coelhos Nova Zelândia foram utilizados. A diabete foi induzida em 13 coelhos com 8 semanas de idade com injeção intravenosa de 100 mg/kg de aloxano. 13 colehos normais serviram como controle. Após 10 semanas os animais foram mortos com overdose de thiopenthal sódico endovenoso. Os pênis foram dissecados retirando-se um fragmento da porção média sendo fixado em formol 10% tamponado (pH 7.3). Todo material foi processado para inclusão em parafina seguindo a técnica histológica de rotina. Principais medidas: A análise estereológica do colágeno, das fibras do sistema elástico e do músculo liso foi realizada em cortes de 5um no sistema teste M42. Os dados foram expressos em densidade volumétrica (Vv %). A organização de colágeno foi avaliada pela coloração do Picrosirius red sob polarização. Resultados: na túnica albugínea de coelhos diabéticos, houve um aumento de 88% da espessura (p<0.0003) com um acentuado turnover do colágeno. Além disso, o conteúdo de fibras elásticas foi 34% maior (p<0.0001). No CC dos coelhos diabéticos o colágeno diminuiu 45% (p<0.0001) com a presença de um colágeno mais organizado. As fibras do sistema elástico tiveram um decréscimo de 46% (p<0.0001). A diabete induziu um aumento de 11% de colágeno no CE (P<0.0235) com um acentuado turnover do colágeno. No CC de coelhos diabéticos houve um aumento de 40% de músculo liso (p<0.0001), enquanto no CE uma diminuição de 38% (p<0.0001). Conclusão: Os tecidos do pênis foram afetados de formas diferentes pela diabete, possivelmente devido à heterogeneidade celular...

Introdution: Although erectile dysfunction is a frequent problem in patients with diabetes mellitus, few studies have evaluated penile structure alteration in this condition. Aim: To assess the volumetric density of collagen, elastic system fibers and smooth muscles cells in the corpora cavernosa (CC), corpus spongiosum (CE) and tunica albuginea (TA) in the penis of diabetic rabbits. Methods: Twenty-six New Zealand white rabbits were used. Diabetes was induced at 8 weeks of age in 13 rabbits by intravenous injection of 100 mg/kg of alloxan. The remaining 13 rabbits served as a control group. After 10 weeks, the rabbits were killed using sodium thiopenthal. Mid-shaft fragments of the penis were obtained and processed by routine histological techniques. Main Outcome Measures: Stereological analysis of collagen, elastic system fibers and smooth muscle was performed in 5-um sections by using a M42 System Test grid. Data were expressed as volumetric density (Vv - %). Collagen organization was evaluated by Picrosirius red staining under polarization. Results: In the TA of diabetic rabbits, thickness increased by 88% (p<0.0003) with an enhanced collagen turnover. Moreover, the elastic fiber content was 34% higher (p<0.0001). In the CC of diabetics, collagen was diminished by 45% (p<0.0001) with a more organized collagen. The elastic fibers were decreased by 46% (p<0.0001). Diabetes induced a 11% increase in CS collagen (p<0.0235) with an enhanced collagen turnover. Smooth muscle in the CC of diabetic rabbits was increased by 40% (p<0.0001), whereas in the CS it was decreased by a similar amount (p<0.0001). Conclusion: Penile tissues were affected differently by diabetes, possibly due to cellular heterogeneity. These changes could have an impact on blood flow and tissue resistance, and therefore, might adversely affect erection...

Penile strangulation by home-made erectile device

A 44-year-old man was admitted with penile edema and pain after having forced a narrow ring of cast iron around the base of his penis five days earlier. He was able to void without problems and there was no evidence of urinary retention. The patient, his general practitioner, and a general surgeon failed to remove the ring by various compression maneuvers. The patient was admitted to the department of urology. However, we had no instruments in our armamentarium capable of cutting cast iron. We contacted the engineering workshop of the hospital, where the engineers recommended the use of an electric iron saw. In order to protect the soft tissue from the sharp teeth of the saw a metal blade covered with a rubber sheet was passed under the iron ring. To prevent heating the saw blade was irrigated with cold water. The patient was given a muffler to protect his hearing. The ring was cut in two places and could be removed without damage to the skin. The patient was discharged the next day. One year later he reports having normal erectile function and no voiding problems

Pulsed and Color Doppler Sonographic Findings of Penile Mondor's Disease

This report describes the color and pulsed Doppler US findings of penile Mondor's disease. The pulsed Doppler US findings of penile Mondor's disease have not been previously published, so we report here for the first time on the cavernosal arterial flow signal pattern of penile Mondor's disease. Penile Mondor's disease is rare disease that's characterized by thrombosis in the dorsal vein of the penis. The previous reports on penile Mondor's disease are concerned with the color Doppler US finding without the flow signals in this area, but these findings are insufficient to understand the hemodynamics in penile Mondor's disease. We report for the first time on a cavernosal artery flow signal pattern of low peak systolic velocity and high-resistance.

Cavernous body reduction in four patients with erectile dysfunction due to insufficient venous occlusion and a deficit of elastic fibers in the tunica albugínea

INTRODUCTION: The corpora cavernosa are cylindrical vessels containing fluid under pressure. Thus, if cavernous wall resistance decreases, the radius increases and internal pressure decreases (LaPlace's law). We reasoned that if we decrease the corpus cavernosum radius, by excising a strip from each tunica albuginea, intracavernous pressure would increase during erection. MATERIALS AND METHODS: We treated with this procedure, four patients (mean age 41.5) with long-standing erectile dysfunction due to veno-occlusive dysfunction, non-responders to phosphodiesterase-5 inhibitors and intracavernous PGE1 injection. RESULTS: Two months post-surgery, intracavernous PGE1 (40 mcg) induced a satisfactory erection in two patients and a 45 percent and 58 percent tumescence in the other two. PGE1 responders also responded to 100 mg sildenafil. After 100 mg sildenafil and 20 mg tadalafil, the two non-responders had erections that enabled penetration but were short lasting. CONCLUSION: The procedure described could be more effective than cavernous revascularization operations. The results seem to confirm the mathematical assumptions.

Free serum testosterone level in male rats treated with tribulus alatus extracts

OBJECTIVE: The present study was undertaken to investigate the effect of Tribulus alatus extracts on free serum testosterone in male rats. MATERIALS AND METHODS: Free serum testosterone level was measured in male rats treated with alcoholic extracts of the aerial part without fruits, fruits of Tribulus alatus and their fractions. RESULTS: All tested extracts showed significant increase in the level of free serum testosterone when compared to that of corresponding control, p < 0.05. Statistical comparison of all groups revealed that the maximum level was found in groups treated with chloroformic and ethanolic fractions of fruits extract. CONCLUSION: Tribulus alatus extract appears to possess aphrodisiac activity due to its androgen increasing property.

Neurovascular anatomy of the penis and pelvis in Thai males: applications to male-to-female and pelvic surgeries.

OBJECTIVE: To determine the neurovascular profiles in the pelvis and penis for applying to sex reassignment surgery. MATERIAL AND METHOD: Dissection of the pelvis and penile shaft was performed in 12 soft-preserved and 32 fresh adult male cadavers respectively. The neurovascular structures were located and documented, and the distances between anatomical landmarks were measured. Thirty-two specimens from the glans penis were obtained for immunohistochemical analysis to analyze its innervation and blood supply. RESULTS: Several anatomical variations of penile arterial supply were found. They are the presence of the accessory pudendal artery, multiple cavernous and bulbourethral arteries. The unilateral dorsal artery was observed in 10 of 32 cadavers, predominantly on the left. From the root to the neck of the penis, the dorsal nerves were divided into two groups. The first group of fibers innervating the glans coursed along the dorsolateral surface of the shaft and pierced the entire area of the corona. The other group diverged to distribute throughout the lateral surface to innervate the lateral and ventral portions. The mean distance between the left and right medial main branches that terminated in the glans was 1.18 cm. Immunohistochemical analysis revealed that the main nerves, after entering the glans, divided into terminal branches that concentrated around urethra. A mean distance from the main nerves to the epithelium was 0.71 cm. CONCLUSION: This detailed anatomy in the pelvis and along the penis should provide a valuable guide for sex reassignment surgery and intrapelvic operations.

Spontaneous resolution of delayed onset, posttraumatic high-flow priapism.

Priapism is an uncommon but serious condition with major long-term sequelae. The commoner, ischemic variety is a medical emergency requiring immediate intervention in order to avoid erectile dysfunction. However,the high flow variety is non-ischemic and the patient may not seek immediate therapy. The options of management for this rare, painless form of priapism vary from conservative therapy to embolization of the internal pudendal artery or, in some cases, surgery that may result in subsequent erectile dysfunction. We present a case of a 24-year-old man who presented with priapism of six-day duration, 10 days after perineal injury. Doppler ultrasonogram of the penis revealed a cavernosal artery pseudoaneurysm. Pudendal artery angiogram done four days later revealed no leak and the priapism subsided spontaneously with subsequent return of normal erections.

Does prolonged semi-erection in prepubertal high flow priapism result in increased penile size?

High flow priapism is a rare pathology resulting mainly from trauma to the perineum leading to arterial-lacunar fistula. Management includes arterial embolization using absorbable material, as well as conservative approach. In this case, the effect of prolonged semi-erection in prepubertal high flow priapism on increased penile size is discussed

Preoperative corporal biopsy as a predictor of postoperative results in venoocclusive erectile dysfunction

Our aim was to investigate the association of corporeal cavernosal pathology with venoocclusive erectile dysfunction [ED] and whether preoperative corporeal biopsy can help predict postoperative results. Thirty-six patients with venoocclusive ED underwent corporeal cavernosal biopsy and venous ligation. Preoperative assessment included complete physical examination, international index of erectile dysfunction [IIEF] scoring, nocturnal penile tumescence, penile Doppler ultrasonography, cavernosography, and, if needed, cavernosometry. Three months postoperatively, all patient parameters were reevaluated and compared with the preoperative results. Biopsy results of 43 patients with penile fracture were used for controls. The mean age of the patients with ED was 32.1 +/- 8.6 years. The IIEF score and peak systolic velocity of the cavernosal artery in the patients did not differ postoperatively. The mean end diastolic velocity, however, decreased from 11.0 cm/s to 5.1 cm/s [P=.023]. Only 2 patients had satisfactory penile rigidity after venous ligation. Pathologically, 23 patients had a slight decrease of cavernosal smooth muscle cells, while in 9 patients, the cavernosal smooth muscles were markedly decreased and replaced by collagen fibers. Four patients had normal histologies, and all responded either partially or completely to surgical therapy. In the control group, 41 of 43 patients had normal histologies, and 2 had a slight decrease of smooth muscle cell mass. Decreased cavernosal smooth muscle mass may impair erectile function. Its association with venoocclusive ED may be a poor prognostic factor of the outcome of surgical therapy. For the preoperative evaluation of patients, we propose cavernosal biopsy

SS-Penogram: a New Diagnostic Test for Erectile Dysfunction

The clinical reports on Sildenafil sulfate (Viagra) are mainly based on individual observations. However, there is a paucity of objective studies in the literature. In order to objectively examine the effect of Sildenafil, a SS (Sexual Stimulation)- Penogram that is a non-invasive, simple and physiologic method was developed using a radioisotope (RI). One hundred and four SS-penograms were performed on patients who had a documented erectile dysfunction (ED) lasting for more than 6 months. After an intravenous injection of 99mTc-RBC (15 mCi), the first penogram was taken immediately after sexual stimulation, which was done by 30 minutes of erotic videotape viewing. Forty minutes after administering 25 to 100 mg of Sildenafil, a second penogram was taken. The characteristics of each penogram were analyzed according to a previously reported method. The results were graded as follows; Type I(normal function; 5 min or more of peak erectile response with an induction period of 1 to 6 min), Type II-A (impossible function type; i.e., showing less than 2 times the basal radioactivity level), Type II-B (the unstable type; showing less than 5 min of peak erectile response), and Type II-C (the delayed type; which showed a delay of more than 15 min after the start of sexual stimulation). The patients were grouped according to their response after Sildenafil administration, and the effect of Sildenafil was assessed by comparing the radioactivity from between 7 to 22 minutes and the changes in the characteristics of the penogram. The mean age of the patients was 44.9 +/- 10.2 (23 - 68) years. In the first penogram, Type I was found in 12 patients, and Type II-A in 14, Type II-B in73, Type II-C in 1 and a mixed (II-B + C) type was found in 4 patients. A second penogram after Sildenafil administration, showed Type I in 46 patients, and Type II-A in 10, Type II-B in 46 and a mixed type was found in 2 patients. The responses after Sildenafil were categorized as follows: 1) An excellent response group (consisting of 56 patients-53.9%); Those who showed greater than 50% increase in the RI area after Sildenafil treatment. 2) A good response group consisting of (23 patients-22.1%); i.e., those who showed a less than 50% but greater than a 20% increase in the RI area after Sildenafil administration. 3) A borderline group (consisting of 15 patients-14.4%); showing less than a 20% change in the RI area after Sildenafil treatment. 4) non-response group (consisting of 10 patients-9.6%). The therapeutic efficacy of Sildenafil, as determined by the SS-penograms, revealed that there was an augmentation in the erectile capabilities in 76% of men (79/104) but a non-response was observed in 9.6% (10/104). The efficacy of Sildenafil on the SS-penogram did not correlate with the patient's age (p=0.198). It is believed that the SS-penogram can be used to accurately evaluate the natural erectile status in sexual and pharmacological stimulation, and provides the most objective erectile response in any therapeutic trial. Consequently, the primary challenge for any erectile dysfunction remedy is to be able to demonstrate its efficacy. A further evaluation is warranted in the non-response group, which was not based on any severe organic dysfunction.